奶牛γ干扰素基因的高效表达及活性测定

经刀豆素(conA)刺激诱导奶牛外周血淋巴细胞,应用RT-PCR方法从其总RNA中对奶牛γ干扰素基因cDNA进行扩增,然后将特异性片段连接到pMD18-T载体,测序结果表明,与已知序列同源性为100%.然后将特异性片段连在pRLC载体上进行表达,经SDS-PAGE分析,原核表达产物为16kDa的重组蛋白,占菌体总蛋白的42%,表达产物以包涵体形式存在.经7mol/L盐酸胍的变性液溶解及0.5mol/L盐酸胍复性液处理,表达产物进行脱盐、凝胶层析纯化,细胞病变抑制法结果表明,重组牛IFN-γ具有较高的干扰素活性,约为6.0×105U/mg.     

奶牛α干扰素在毕赤酵母中的分泌表达及其生物活性测定

提取经新城疫病毒诱导培养的奶牛外周血淋巴细胞总RNA,应用RT-PCR方法扩增出奶牛α干扰素成熟蛋白基因,然后将特异性片段连接到pMD18-T载体,测序结果表明,扩增片段为牛α干扰素成熟蛋白序列,与Genebank上发表的α1干扰素序列同源性为98%。然后将特异性片段连接到含分泌信号肽序列的Pichiapastoris表达载体pPICZαA上,将重组质粒经SacI酶切线性化后电转化导入毕赤酵母菌株X-33。转化子经PCR分析鉴定后利用甘油增菌和甲醇诱导,实现了BoIFN-α在毕赤酵母系统中的分泌表达。SDS-PAGE结果显示表达产物分子量约为23kDa,比其推导结果(20kDa)略大,推测可能是因为表达产物发生了一定程度的糖基化。细胞病变抑制法结果表明,重组牛IFN-α具有较高的干扰素活性,约为4.1×10⁵U/ml,经微量蛋白测量仪测得,其表达量约为80μg/ml,比活为5.1×10⁶U/mg。     

猪β-干扰素的原核表达及其对猪流行性腹泻病毒的抑制作用研究

本研究通过PCR技术克隆了猪β干扰素全基因,设计引物亚克隆猪β干扰素成熟蛋白编码基因并对,5’端1个稀有密码子进行了大肠杆菌偏嗜性改造。构建了猪IFN-β原核单纯表达载体pRLC-poIFNβ,实现了poIFN-β在大肠杆菌中的表达,表达产物约占菌体总蛋白的17.3%。表达产物以包涵体形式存在,用含6mol/L盐酸胍的变性液溶解及含GSH-GSSG复性液复性处理,复性后的表达产物经凝胶层析纯化后,MDBK细胞-VSV病变抑制法测定结果表明,重组猪β干扰素具有良好的抗病毒活性,约为5.6x105U/mg。用重组猪β干扰素处理猪肾传代细胞PK-15后,细胞病变抑制法(CPE50)测定结果表明:重组猪β干扰素可显著抑制猪流行性腹泻病毒(PEDV)的感染。     

猪β-干扰素的原核表达及其对猪流行性腹泻病毒的抑制作用研究

本研究通过PCR技术克隆了猪β干扰素全基因,设计引物亚克隆猪β干扰素成熟蛋白编码基因并对,5'端1个稀有密码子进行了大肠杆菌偏嗜性改造.构建了猪IFN-β原核单纯表达载体pRLC-poIFNβ,实现了poIFN-β在大肠杆菌中的表达,表达产物约占菌体总蛋白的17.3%.表达产物以包涵体形式存在,用含6mol/L盐酸胍的变性液溶解及含GSH-GSSG复性液复性处理,复性后的表达产物经凝胶层析纯化后,MDBK细胞-VSV病变抑制法测定结果表明,重组猪β干扰素具有良好的抗病毒活性,约为5.6x105U/mg.用重组猪β干扰素处理猪肾传代细胞PK-15后,细胞病变抑制法(CPE50)测定结果表明重组猪β干扰素可显著抑制猪流行性腹泻病毒(PEDV)的感染.     

猪γ干扰素基因的克隆、表达及其纯化

以RT-PCR方法,从经丝裂原诱导的猪外周血淋巴细胞总RNA中扩增出编码猪IFNγ的基因。经测序证实后插入载体pJLA503,并实现在大肠杆菌中的高表达。表达产物以包涵体形式存在,经7mol/L盐酸胍变性及精氨酸存在的情况下复性。再经DEAE-Sepharose离子交换柱、Sephdex-200凝胶过滤柱分离获得电泳单一纯猪IFN-γ蛋白,细胞病变抑制实验检测纯化产物有干扰素活性。     

脑药物转运载体——抗转铁蛋白受体单链抗体的克隆表达及鉴定

为构建特异性的脑药物转运载体 ,分段合成了抗大鼠转铁蛋白受体的单链抗体基因 (Ox2 6 scfv) .经重叠PCR拼接成完整片段 ,克隆入pUC19载体中 ,测序正确后克隆到大肠杆菌表达载体pET 15b E .tag上 .IPTG诱导 ,表达产物分子量为 2 9kD ,约占菌体总蛋白量的 4 0 % .包涵体经 6mol L盐酸胍变性后 ,过SephacrylS 30 0HR分子筛柱复性蛋白 .免疫酶染色实验表明 ,该单链抗体能与转铁蛋白受体特异性结合 ,为建立以转铁蛋白受体为介导的血脑屏障转运载体打下了基础     

美洲大蠊变应原Cr PI的表达、纯化与免疫学特性鉴定

以阳性噬菌体克隆为模板,通过PCR扩增出目的基因片段并克隆入T载体,经测序证实为美洲大 蠊Periplaneta americana变应原Cr PI后,将该基因亚克隆入表达载体pGEX-5X-1。美洲 大蠊变应原Cr PI在大肠杆菌中得到高效表达,但主要以包涵体形式存在于沉淀中。目的蛋白溶 于6 mol/L盐酸胍并经稀释复性后,经Glutathione Sepharose^TM4B亲和层析,纯度达 90%以上。以蟑螂过敏病人血清进行免疫印迹检测,结果显示重组变应原具有良好的IgE结合活 性。     

颗粒裂解肽G13结构域在大肠杆菌中的高效融合表达

为高效表达颗粒裂解肽G13结构域并避免G13对宿主菌的毒性, 将人工合成的编码G13的基因片段, PCR扩增后克隆于原核表达载体pThioHisA中, 构建了重组表达载体pThioHisA-G13, 将其转化于大肠杆菌BL21(DE3)中, 经IPTG诱导表达融合蛋白Trx-G13, 表达产物以包涵体的形式存在, 其表达量约占细菌总蛋白的58%。包涵体蛋白经 8 mol/L尿素溶解后, 再经CNBr切割, 阳离子交换层析, 得到纯化的重组G13结构域。琼脂糖扩散法检测表明重组G13结构域多肽具有抗菌活性。     

猪干扰素-γ基因在毕赤酵母中的分泌表达

将去除信号肽的猪干扰素-γ（PoIFN-γ）基因置于酿酒酵母α因子分泌信号的DNA序列后, 构建成pPIC9K-α-PoIFN-γ分泌型重组表达载体, 电转化导入毕赤酵母GS115中,经G418筛选后获得2株多拷贝插入的重组子。SDS-PAGE和Western blot分析结果表明,所获得的重组子能够分泌表达出17kD和23kD左右的PoIFN-γ特异蛋白,其表达量为108mg/L,占培养液总蛋白的60%。实验首次在毕赤酵母表达系统中实现了PoIFN-γ基因的分泌表达。     

鸡传染性支气管炎病毒核蛋白基因在大肠杆菌中的表达及抗原性初步研究

为了研究重组鸡传染性支气管炎病毒核蛋白能否作为群特异性诊断抗原加以应用,将鸡传染性支气管炎病毒国内分离株IBV—LX4核蛋白基因亚克隆于大肠杆菌原核表达载体pPROEX^TM HT中。构建拟表达重组鸡传染性支气管炎病毒核蛋白的重组质粒pPROEX^TM HT—N。经核苷酸序列测定后,阳性质粒转化大肠杆菌DH5α,并进行诱导表达。表达产物经SDS-PAGE、Western blot鉴定,表明核蛋白在大肠杆菌中获得了表达,表达产物是分子量分别为约56kD和45kD的蛋白,其中分子量为56kD的蛋白表达量约为菌体总蛋白的13％。包涵体被6mol盐酸胍裂解后。通过镍离子亲和树脂进行了纯化,并用纯化的分子量为56kD的重组蛋白免疫新西兰白兔,所获得的兔抗鸡传染性支气管炎病毒核蛋白多克隆抗体,分别与不同致病型的鸡传染性支气管炎病毒进行琼脂扩散反应,结果表明。该多克隆抗体可与各不同致病型毒株发生反应。这初步表明重组鸡传染性支气管炎病毒核蛋白。可作为群特异性诊断抗原用于该病毒的诊断中。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various